New Cat Vaccine Could Be Break In Cancer Fight

February 01, 1985|By Mary Daniels and Ronald Kotulak.

A new vaccine against feline leukemia--described as the first effective anti-cancer vaccine--may represent a technological breakthrough in the fight against some human cancers and AIDS, according to a leading cancer researcher. Dr. Robert Gallo, chief of the laboratory of tumor cell biology at the National Cancer Institute in Bethesda, Md., said Thursday that if the new vaccine for cats proves effective, ``it could be an extremely important model for man.``

AIDS researchers cautioned, however, that although a number of laboratories are working on an AIDS vaccine, its development is years away.

Gallo, discoverer of the T-cell leukocyte in human leukemia and the AIDS agent HTLV-111, said, ``It will certainly be the prototype for some of the things we`d like to do with people.``

The vaccine, under the trade name Leukocell, is being distributed this week to veterinarians by Norden Laboratories of Lincoln, Neb.

Feline leukemia is the leading cause of death among cats.

Norden officials said Leukocell is successful against the disease because researchers were able to isolate a protein, which they called p15E, from the feline leukemia virus. They learned that the key to a successful vaccine was the absence of p15E because the protein is immunosuppressive, which means it interferes with the ability of the cat`s immune system to respond to an injection of feline leukemia virus.

Dr. Juris Kalnins of Wheaton Animal Hospital in Glen Ellyn, a veterinarian who has been issued the new vaccine, said the feline leukemia virus ``is a very peculiar virus in that it has certain properties by which it destroys the immune system of the cat. In its action, it is very similar to AIDS.``

AIDS, or Acquired Immune Deficiency Syndrome, destroys a person`s immunity and so far has been found primarily among homosexuals and bisexuals, intravenous drug abusers, Haitians, hemophiliacs and recipients of blood transfusions.

Kalnins said the new vaccine ``works on three planes. It forms antibodies against the feline leukemia virus, it works against the part of the virus that produces the immunosuppression in the cat`s system that lays it open to any number of other diseases, and it works against the formation of hard tumors.`` The vaccine was developed by Dr. Richard Olsen and his colleagues at Ohio State University, who experimented with and patented the process by which a vaccine successfully protected cats against the leukemia. Olsen aided Norden in developing the commercial version.

The introduction of Leukocell comes after more than 10 years of research. The virus that causes feline leukemia, which is highly contagious among cats but not transmittable to humans, was isolated in the early 1970s. Since then there have been several unsuccessful attempts to develop a vaccine.

``There were at least three different kinds,`` said Dr. Audrey Hayes, staff member of the oncology department and the chief feline specialist at the Animal Medical Center in New York, which she said tested ``a hundred cats for Norden before they came out with the vaccine.``